Speed-increasing agents for an nu-vinyl amine and organic halogen dye former system



United States Patent 3,359,105 SPEED-INCREASING AGENTS FOR AN N-VINYLAMINE AND ORGANIC HALOGEN DYE FORM- ER SYSTEM Eugene Wainer, ShakerHeights, Ohio, assignor to Horizons Incorporated, a corporation of NewJersey No Drawing. Filed Mar. 10, 1965, Ser. No. 438,760

11 Claims. (Cl. 96-48) ABSTRACT OF THE DISCLOSURE Previously knownphotosensitive composition comprising an N-vinyl compound such asN-vinylcarbazole, a free radical generating organic halogen compoundsuch as CBr is enhanced by the addition of sulfur and/or nitrogencompounds, such as Z-mercaptobenzothiazole and/ or tetrazoles.

This invention relates to light sensitive compositions such as thosedescribed in United States Patent 3,042,517 issued July 3, 1962. Moreparticularly, it relates to the addition of certain classes of nitrogenand/ or sulfur containing organic compounds to photosensitivecompositions based on N-vinylcarbazole and CBr In the above noted patentI have described light sensitive compositions consisting essentially ofsuitable N-vinyl com-pounds and suitable organic halogen compounds,which compositions when exposed photographically yielded a latent imagewhich was rendered visible by means of either heat or infrared.

It has now been found that the photographic speed of such compositionsis significantly increase-d by the addition of various sulfurand/ ornitrogen-containing heterocyclic compounds of the types hereinafterdescribed.

To illustrate that the addition of such compounds is effective inincreasing the photographic response of such compositions to radiationin the range of 3900 Angstrom units to 4500 Angstrom units, i.e. toradiation in the visible, the following composition was prepared:

Percent in benzene Polystyrene (1 cc) l0 Eicosane (1 cc.) 25 CBr, (5cc.) 25 N-vinylcarbazole (3 cc.) 25

This formulation was coated ,to 0.003 inch wet thick- DENSITIES FORSECOND EXPOSURES TO MONO- CHROMATOR (5.0/5.0 SLIT WIDTHS) Wavelength A.With MBT Without MBT To show that this increase in speed is not confinedto 2-mercaptobenzothiazole, the compounds listed below ice were testedusing the following photosensitive formulation:

10 cc. polyvinylchloride (PVC-30), 10% in tetrahydrofuran 2 gramsN-vinylcarbazole 1.6 grams CBr 40 mg. of compound being tested.

The resulting formulation was coated on gm. baryta paper in the mannerdescribed in the above noted patent to 0.003 inch wet thickness.

The coatings were exposed in four different Ways as follows:

A. To a GE. sunlamp for 60 seconds through a 21 step wedge using aprinting frame with a glass face. Sixty seconds exposure was used toinsure a good number of steps for counting.

B. Same as A, except a photoflood lamp was used.

C. Exposures were made to a sunlamp for l, 5, 30 and 60 seconds withouta negative (step wedge) or glass plate both of which will absorbultraviolet radiation from the sunlamp and pass only visible radiation.

D. Same as C except a photoflood lamp which has some U.V. emission butvery much less than sunlamps.

After exposure the samples Were heat developed for 5 seconds at C. in anoven with rapidly moving air.

The table below shows the results of these exposures in terms of maximumdensity realized with each exposure and where step wedges were used, thenumber of steps observed.

From this it will be seen that mercapto compounds selected from thegroup consisting of mercapto benzothiazoles, and mercaptotetrazoles areeffective in significantly increasing the response of N-vinylcarbazole,car bon tetrabromide compositions upon exposure to light and subsequentheat development.

For the compositions given in Table I the amount of themercaptobenzothiazole or mercaptotetrazole compound which yieldsignificantly improved results may be varied between 5 and 150milligrams of this type of addition for the specific base formula givenand optimum amounts are in the range of 40 to 75 milligrams in the basecomposition given. In other words, the improvement begins to benoticeable at a 5 milligram addition and begins to reach a maximum inthe range of 40 to 75 after which further additions yield no largeimprovement on the increase in speed and increase in density atequivalent exposures.

The compositions of the instant invention are not confined to thosedescribed in the foregoing example as will be apparent from the datawhich follows and it is to be understood that each and any one or moreof the constituents utilized in the example may be replaced byequivalent or similar materials.

Thus, instead of CBr other organic halo-gen compounds may be used, suchas pentabromoethane, iodoform and other compounds such a thosespecifically described in United States Patent 3,147,117 issued Sept. 1,1964 and represented by the general formula RC-X wherein each Xrepresents a chlorine, bromine or iodine atom and not all of the Xs needbe the same, and R represents alkyl, aryl, aralkyl, haloalkyl, aroyl,Cl, Br, I or H.

The same holds true for the film forming binder material, the presenceof which is optional since when it is absent the composition can beapplied to paper or other absorbent substrates and utilized when carriedon such supports. Instead of polystyrene or polvvinylchloride, utilizedin the preceding examples, other homopolymers or copolymers or mixturesof film forming materials may be utilized. For reasons not entirelyunderstood, some film forming materials appear to'intluence thephotosensitivity TABLE I.RESULTS OF EXPOSURES TO U.V. AND

ING COMPOSITIONS Exposure A B C D Compound Added 60 sec. to sunlamp 60sec. to photoflood Exposure to sunlamp Exposure to photoflood throughstep wedge through step wedge without step wedge or without step wedgeor glass 01 print frame glass of print frame No. of Max. N0. of Max.Time, Density Time, Density steps density* steps density* secs. secs.

No Mercapto Compound (control) 8 1.0 1.10 1 .18 1 .16 5 21 5 19 30 60 3044 60 1.52 60 .80 ltlercapto-benzothiazole 9 1. 24 14 2. 04 l 35 1 28 52.13 5 1.17 30 2.46 30 2.10 60 2. 42 60 2.01 Phenylmercapto tetrazole. 81- 14 6 0.90 1 .18 1 32 5 58 5 78 30 1.38 30 2.15 60 1. 52 60 2. 22Methylmercapto tetrazole 10 1.26 11 1. 08 1 .17 1 .195

5 .23 5 .46 30 95 30 1. 23 60 1.95 60 1.50 Ethyl mercapto tetrazolc 81.12 8 1, 1 22 1 5 72 5 24 Q0 30 1. 20 60 1.85 1.39

Density is white light reflection density using a Photovoltdensitometer.

of the composition to a greater extent than others as may be seen from acomparison of the examples which follow as compared with the precedingexamples.

Finally, it should be noted that instead of the mercapto compoundsutilized in the preceding examples many of the several classes of thesulfur-containing organic compounds described in copending United Statespatent applications Ser. No. 270,551 and 398,097 filed Apr. 4, 1963 andSept. 21, 1964 and now United States Patents 3,285,- 744 and 3,342,602,respectively or mixtures containing two or more of such compounds may beutilized to enhance the response of the N-vinylcarbazole/CBn; mixture.

Suitable sulfur-containing compounds include the followingsulfur-containing organic compounds:

(1) Mercapto compounds of the type R'SH wherein R is a heterocyclicnucleus of the type commonly used in cyanine dye chemistry, as outlinein column 4 of US. Patent 3,100,703 issued Aug. 13, 1963;

(2) Disulfides of the type R'SS-R' wherein R has the same meaning as in1 above;

'(3) Disulfides of the general formula wherein R" is selected from thegroup consisting of H, lower alkyl and aryl; and

(4) Cyclic sulfur compounds wherein the sulfur is attached to a carbonatom in a heterocyclic ring wherein the same carbon atom is attached totwo non-carbon atoms, e.g. as in rhodanine or tetrazole.

In addition to the combination of essential constituents, namely theN-vinyl compound, organic halogen compound and sulfur-containing organiccompound, the compositions of this invention may contain othersubstances added for a specific purpose. One particularly preferredgroup of compounds which may be included in the compositions of thisinvention are the triaryl compounds of Group V elements particularly thetriphenyl compounds of antimony, phosphorus, arsenic and bismuth each ofwhich has been found to be effective in the diminishing or totalelimination of the fogging occurring as a result of the thermaldevelopment step.

For the purpose of amplifying the disclosure in the preceding example, abase composition was made up as follows:

Percent in benzene (1) Elvax No. 220 (1 cc.) s- 10 (2) Eicosane (1 cc.)25 (3) Carbon tetrabromide (5 cc.) 25 (4) N-vinylcarbazole (3 cc.) 25

Elvax is a copolymer of polyethylene and polyvinylacetatc manufacturedby the duPont company.

As a control this formulation was coated under a Wratten 1 seriessafelight at a 0.003" wet thickness on pound baryta paper and afterwhich was allowed to dry in the dark for 30 minutes before exposure.Comparisons were made between exposure results obtained on this controland the composition with the various sulphur compounds added to thisformulation as listed in Table II. In order to produce the sulphurcontaining composition the designated weight of the sulphur compoundlisted in Table II was added to the base composition just described,thoroughly stirred until dissolved, and again coated in a 3 mil wetthickness on baryta paper.

Each of these compositions was then exposed to a 500 watt photofioodreflector type lamp, placed at a distance of 12" and the exposure timein each case was 5 seconds. The exposure was made behind a mask so thata sharp demarcation between exposed and unexposed conditions could beestablished. Immediately after exposure of the photoflood lamp, thesample was developed with an infrared lamp fitted with a ruby glassenvelope which filtered out all radiation below 6500 A. The specimen wasmaintained at a distance of approximately 3 to 4" from the infrared lampand moved continuously during thermal and infrared development toprevent localized overheating. A time period of development of 1 minuteexposure to the inrfared lamp was utilized in each case. Under theconditions specified background fog development less than 0.1 unit ofdensity and generally in the range of 0.05 unit of density could beachieved easily. An infrared development much longer than this periodyielded an undesirable buildup of background fog. The improve ment innet density (measured density minus base plus fog density) is listed inTable H.

TABLE II Net density at 5 sec. Weight in exposure to Addition to basecomposition (above) mg. of 500 watt addition photofiood at distance of12 inches (1) No sulphur compound (control) 0.32 (2)2-mercaptobenzoxazole 100 2.42 (3) ZIEGXCBDtO-fi nitrobenzothiazole 502.62 (4) 2-rnercapto-4 phenylthiazole 60 2. 73 (5) 6-amino2-mercaptobenzothiazole. 30 3.0+ (6) 2-ruercapto-4,6,6trimethyl-1,3-thiano 100 1. 82 (7) 2-mercapto-4-phenylthiazole 40 2. 91 (8) Diphenyldisulfide 25 3. (9) Bis(3-phenyl-2-indolyl) disulfide 40 1.96 (10)Tetramethyl thiouram disulfide 25 2.91 (11) Rhodanine 20 3. 0+ (12) 2,4thiazolidine dione 100 2.22 (13) 2-mercaptopyridine 100 2.15 (14)2-mercaptobenzoic acid 50 1.82 (15) 2-rnercaptobenzoic acid. 25 3 0+Z-mercaptobenzothiazole. 25

From the data presented in Table II it will be seen that the variousgroups of sulfur containing compounds are all effective in significantlyincreasing the response of N-vinylcarbazole/carbontetrabromidecompositions upon exposure to light and subsequent heat development.

For the additions in Table II and with the specific base compositiongiven improvement in net density at a specific exposure starts to makeitself evident with the additions as low as 2 milligrams of theindicated additive and optimum additions are in the range of 25 to 100milligrams. Doubling the high level amounts to 200 milligrams, forexample, yields no further improvement in the speed or in thedevelopment of net density.

The earlier emergence of the effect of the organic sulphur compounds onthe base composition utilized in Table II appears to be a function ofthe difference in the base composition itself over that used in Table Irather than the specific sulphur compounds being added.

As previously indicated it is also advantageous to add aryl Group Vbcompounds to compositions of the type described for the purpose ofminimizing the fogging since in normal thermal development in theabsence of such triaryl compounds care must be taken to prevent thedevelopment of background fog in the thermal step, whereas in thepresence of the triphenylstibine compound the composition could bedrastically over-developed and complete restraining of background fogdevelopment is observed.

The following composition was shown to be particularly effective forthis purpose:

(1) 10 cc. of polyvinylchloride in freshly distilled tetrahydrofuran (2)2 grams of recrystallized N-vinylcarbazole 3) 1.6 grams of carbontetrabromide (4) 50 milligrams of mercaptobenzothiazole 2 cc. of a 1percent solution of triphenylstibine in benzene The above compositionwas prepared under a Wratten 1 series safelight and coated at a 0.003wet thickness on a 135 gram baryta paper and allowed to dry for /2 hour.Thereafter, it is exposed through a negative for 5 seconds to a 500 wattphotofiood at a distance of 12". The image portions of this compositionwere developed to a net density of between 2.5 and 3 in the imageexposed areas after 60 seconds development to the infrared lampdescribed previously. Fog levels remained regularly below 0.05 unit ofdensity under such conditions. Continuing the infrared development for aperiod of 5 minutes longer raises the fog level from 0.05 to about 0.07,whereas in the absence of the triphenylstibine composition continuingthe infrared lamp development for 2 minutes rather than the 1 minuterecommended previously raises the background fog level to 0.32 units ofdensity and as the infrared development is continued for a period of 5minutes the background fog level rises above a density of 1.5 making theresult effectively useless under such exposure conditions for practicalpurposes.

Examination of optimum levels of the triphenylstibine compound for thisspecific composition indicates that significant and beneficial resultsare obtained in a range of 0.5 to 4 cc. of a 1 percent triphenylstibinewith respect to fog restrainment without major reduction on photographicspeed when net densities above 2.0 in the image portions are required.Concentration above 4.0 cc. of the stated triphenylstibine solutionstart to reduce photographic speed and the maximum levels of net densitywhich can be achieved.

In the composition just given, involving a combination ofN-vinylcarbazole, carbon tetrabromide, mercaptobenzothiazole and theminor amount of triphenylstibine, replacement of the carbon tetrabromidewith 2.0 grams of pentabromethane yielded a thermally developed-outdensity of 2.5 after exposure to the photofiood lamp for 5 seconds at adistance of 12" with infrared development for a period of seconds.Replacement of the 1.6 grams of carbon tetrabromide in this same baseformulas with 0.7 grams of iodoform yielded a net density of 2.5 afterexposure to the photofiood and a 100 second infrared lamp developmentafter a photofiood exposure of 2 sheets.

Proportions Preferably the relative proportions of N-vinyl compound toorganic halogen compound should be between 5 and 0.5 part by weight ofN-vinyl compound for each part by weight of organic halogen compound;the amount of organic sulfur containing compound should be between about2.5 and 100 parts by weight for each 1000 parts by weight of organichalogen compound; and when present, the aryl Group Vb compound should bebetween 5 and 50 parts by weight for each 1000 parts by weight oforganic halogen compound.

I claim:

1. A photosensitive composition comprising:

(a) an N-vinyl amine;

(b) a halogen containing organic compound represented by the generalformula RCX wherein each X represents an atom of chlorine, bromine oriodine and R represents a member selected from the group consisting ofH, Cl, Br, 1, alkyl, aralkyl, aroyl and haloalkyl; and,

(c) a sulfur containing organic compound selected from the groupconsisting of (l) Mercapto compounds represented by the formula R'S-Hwherein R is a heterocyclic nucleus commonly used in cyanine dyechemistry;

(2) Disulfides represented by the formula RSSR wherein R has the samemeaning as in 1 above; and

(3) Sulfur compounds wherein the sulfur is attached to a carbon atom ina heterocyclic ring wherein the same carbon atom is attached to twonon-carbon atoms 2. A photographic film comprising a compositionaccording to claim 1 coated on a support.

3. A composition according to claim 1 dispersed uniformly throughout asupport.

4. A composition according to claim 1 wherein the relative proportion ofN-vinyl compound is between 0.5 and 5 parts by weight for each part byweight of organic halogen compound and the relative proportion oforganic sulfur compound is between 2.5 and 100 parts by weight for each1000 parts by weight of organic halogen compound.

5. A composition according to claim 1 wherein the N-vinyl compound isN-vinyl carbazole.

6. A composition according to claim 5 wherein the organic halogencompound is a halogen containing hydrocarbon.

7. A composition according to claim 5 wherein the organic sulfurcompound is a mercapto compound.

8. A composition according to claim 7 wherein the mercapto compound is amercapto benzothiazole.

9. The composition of claim 1 containing in addition a triaryl compoundselected from the group consisting of triphenylstibine,triphenylbismuthine, triphenylarsine and triphenylphosphine as anantifoggant.

10. A method of photographically producing a visible image whichcomprises preparing a film containing the composition of claim 1,photographically exposing the film to light thereby producing a latentimage in said film, and developing a visible image thereof by applyingthermal radiation to said latent image bearing film whereby said visibleimage is simultaneously developed and fixed.

8 11. The method of claim 10 wherein the thermal radiation is in theinfrared.

References Cited UNITED STATES PATENTS 3,042,516 7/1962 Wainer 96903,042,518 7/1962 Wainer 9690 3,046,125 7/1962 Wainer 96-90 3,275,4439/1966 Wainer 96-90 10 3,285,744 11/1966 Sprague et a1. 9690 J. TRAVISBROWN, Primary Examiner.

NORMAN G. TORCHIN, Examiner.

C. E. DAVIS, Assistant Examiner.

1. A PHOTOSENSITIVE COMPOSITION COMPRISING: (A) AN N-VINYL AMINE; (B) AHALOGEN CONTAINING ORGANIC COMPOUND REPRESENTED BY THE GENERAL FORMULAR-C-X3 WHEREIN EACH X REPRESENTS AN ATOM OF CHLORINE,BROMINE OR IODINEAND R REPRESENTS A MEMBER SELECTED FROM THE GROUP CONSISTING OF H, C1,BR, I, ALKYL, ARALKYL, AROYL AND HALOALKYL; AND, (C) A SULFUR CONTAININGORGANIC COMPOUND SELECTED FROM THE GROUP CONSISTING OF (1) MERCAPTOCOMPOUNDS REPRESENTED BY THE FORMULA R''-S-H WHEREIN R''IS AHETEROCYCLIC NU CLEUS COMMONLY USED IN CYANINE DYE CHEMISTRY; (2)DISULFIDES REPRESENTED BY THE FORMULA R''-S-S-R'' WHEREIN R'' HAS THESAME MEANING AS IN 1 ABOVE; AND (3) SULFUR COMPOUNDS WHEREIN THE SULFURIS ATTACHED TO A CARBON ATOM IN A HETEROCYCLIC RING WHEREIN THE SAMECARBON ATOM IS ATTACHED TO TWO NON-CARBON ATOMS.